1. Field of the Invention
The present invention relates to a sheet conveying device and recording apparatus capable of correcting a conveyance length of a continuous sheet.
2. Description of the Related Art
In a recording apparatus, when a continuous sheet, which is a medium, is conveyed, the surface of the sheet may slip on a conveyer part, causing the conveyance length to deviate from a target value. In such a case, lines may be formed during printing, reducing the printing quality. Thus, the driven amount of the conveying mechanism must be corrected so that the conveyance length is set to the target value. When conveying a rolled sheet, the sheet slippage during conveyance may vary in accordance with the remaining amount of rolled sheet. For example, when the remaining amount of the rolled sheet is large, the slippage is large due to the effect of the inertia brake of the rolled sheet, whereas when the remaining amount of the rolled sheet is small, the slippage is small because the effect of the inertia brake of the rolled sheet is small. There is a known apparatus including a rolled-sheet feeding part equipped with a torque limiter. The apparatus is capable of performing skew correction of a sheet by applying a braking force to the sheet. With such an apparatus, at constant torque, when the diameter of the rolled sheet is large, the braking force is small, whereas when the diameter of the rolled sheet is small, the braking force is large.
Japanese Patent Laid-Open No. 2007-253361 discloses a technique of correcting a driving amount in response to the remaining amount of a rolled sheet.
In a recording apparatus, in some cases, a recording medium is spooled into a roll while applying tension to the recording medium for reasons such as facilitating the handling of the recorded medium or supporting the conveyance. For example, in a recording apparatus that spools a medium at constant torque using a torque limiter, the tension applied to the recording medium varies as the diameter of the rolled sheet changes. Such variation in tension causes the medium conveyance length to deviate from a target value, reducing the printing quality. Thus, for a recording apparatus that has a spooling conveyance mechanism, conveyance must be corrected in accordance with the variation in tension.